Discharge tube with inclosed arc discharge



May 1926. 1,583,593

G. HQLST ET AL DISCHARGE TUBE WITH INCLOSED ARC DISCHARGE IE. 1, Filed Sept. 26, 1922 Patented May 1926..

UNITED, STATES,

PATENT OFFICE.

eiLLEs' 1mm, nxxo oos'rnnnurs, Ann JOHANNES BRUIJNES, or nmnnovmr, 1 NETHERLANDS, nssmnons To nnAmLoozn vENNoo-rscnar rmurs' (11.0m-

namrmzrnnnrnn, or nmnnovmv, nnrnnnmmns.

'mscnmn rune wrrn mcnos'nnanc DISCHARGE.

- Application filed September 26, 192 2. Serial mo; 590,705.

To all whom may concern: 4

Be it known that we, Grnun' HOLS'1,-EKKO Oos'rnmrms, and JOHANNES Bnnmm's, all subjects of .the Queen of the Netherlands, residin at Eindhoven, in the Province of Northrabant, in the Kingdom o f the Netherlands,"ha've invented certain new and useful-1m rovements in-or Relatin to Discharge Tu s with Inclosed Arc Discharges (for which we have filed applications in the Kingdom of the Netherlands on August 30,

1921, Serial 20,229, and on September 1,

1921, Serial 29,256), of whichthe following is 'a specification.

i In discharge tubes with inclosed arc-discharge between fixed electrodes of a refrac ,tory' material in a neutral gas, the hfe 1s determined .by the rate of evaporat on and disintegration of the electrodes. The character of the two henomena and the conditions under whic either occursare as yet.

incompletely known and the-reports issued on the subject .are frequently incorrect.

We have :recognized' that whereas the evaporation increases steadily ata high temperature of the electrodes,v disintegrat on on the contrary occursonly, if the tempera.- ture falls below a certain limit. It is possible to do away with this disintegration entirely or in part, by maintaining the cathode with the aid of outward auxi iary devices at a sufiicientlyhigh temperature e. g; by.

' operating the same as an incandescent through the vgas that the temperature does.

not fall to thatof disintegration. To'that end the electrodes may be shaped so that one electrode envelops the other to a large extent at those places where the arc-dis charge is efi'ected. I

' Incidental to this is the advantage that a "the discharge tube is the tube.

' great partof the evaporated and possibly still disseminated material passesfrom one electrode to the other. Such tubesmay be constructed both for alternating and' for continuous current. I For tubes worked with alternating currentit is suflicient in many cases to construct the electrodes in such a way that each electrode while functioning as an anode reaches such a high temperature that durin "the next half-period its temperature oes not fall to disintegration temperature.

In the latter case, the construction oi the tube may also. correspond to those generally used for-discharge-tubes with inclosed arcdischarge, having fixed electrodes of.tungsten or the like. The conditions for the electrodes aboye referred to may then be obtained by'su'it-abl proportioning a, resistance, choking coi or condenser, connected in series with the discharge tube. In so doing the current density at the electrodes, and consequently the temperature of the electrodes, isregulated and ma be sochosen that each electrode during t e time it is working as an 'anode reaches such a high temperature that during the followin half period the temperature does not fall lowthe limit of disintegration. It will be apparent that the fluctuations of temperature of the electrodes depend on the composition and pressure of the gas'filling and on the shape and position of the electrodes.- A'fluctuation of temperature between the limits according to the present invention may be obtained, however, with .a Iga sfilling of known composition and generally used pressure, whereas the electrodes may be con-. structed, for instance, in known manner in the form of balls fastened to the ends of conducting wires. Supposing, for exam 1e, rovided with e ec-" trodes consistin of ba sof tungsten fastened to the en s of conducting wires and spaced, say 1 mm. apart, the gasfilling consisting of neon or argon having a pressure of about 50cm. of mercury, the object of the present invention may be obtained by connecting the tube to an alternating current of 50 periods and by suitably proportionmg a resistance connected in series with The temperature above, indicated the limit of disintegration may be easily determined for each material by measurement and calculation. For a discharge tube with tungsten electrodes the temperature may "fluctuate, according to the invention, between about 2525 C. and 2725 C. when operating normally.

In the accompanying drawing two different embodiments of the present invention are shown, in which the electrodes'are so constructed and arranged in heat interchange relation to each other, that their temperature is maintained above that of disintegration. Y

Fig. 1 represents a discharge tube having a closed'en-velope 1, which is filled with a neutral gas such as nitrogen, or with a rare gas such as neon or with a mixture. of gases,

the pressure of said gasfilling being in the neighborhoodof 1 atmosphere, forexample 50 cm. of mercury.

@ Within the envelope 1 the electrodes 2 and 3 are fastened to conducting wires 4 and 5, sealed into the stem 6 and outwardly connected to a suitable' tension. If necessary a device, which is not shown in the drawing ,ma be applied for temporarily increasing 1'. e voltage of the circuit, in order to initiate an arc dischargebetween the electrodes 2 and 3.-

The electrodes may both consist of tungsten. The electrode 2 consists 'of a coiled wire which surrounds the electrode 3, consisting of a ball fastened to a wire of materially smaller diameter.

The electrodes are so connected to a source of .directcurrent' that the electrode 2 acts as an anode, the electrode 3 acting as a cathode. I

hen, the arc-discharge is established, both electrodes areheated to incandescence, the current densitybeing regulated by means of a resistance 7 connected in series with the electrodes.

The anode .2, surrounding the cathode 3, imparts heat to the latter so that by suitably proportioning the resistance 7, the temperature of-the cathode 3 is maintained above that of distintegration.

The embodiment, according to Figure 2,

is suitable both for direct and alternating,

current. What has been said in relation to Fig. 1 for the gasfilling, the. gaspressure and the electrode which temporarily acts. as an anodeimparts heat to the other electrode so that the temperature of both electrodes does not fall below the temperature of disintegration, being about 2800v absolute.

In both figures corresponding parts are indicated with corresponding reference numeralsf What we claim is:

1. The method of operating an are discharge lamp, which consists in supplying an excess of energy to the anode above that theoretically necessary to-maintain the arc, the excess energy imparting suflicient heat to the cathode to maintain said cathode above a minimum temperature of disintegra tion during operation. 2. The method of operating an are discharge lamp, which consists in supplying an excess of energy to the'anode and in' transferring to the cathode a suflicient amount of the excess energy in the form of heat to maintain the cathode at a temperature between about 2525 C. and 2725 C. V

3. The method of operating'on alternating current a discharge tube with inclosed arc discharge, which consists in heating the electrodes, during the period of functioning as an anode, to such-a temperature that said electrodes do not cool. down belowthe temperature of disintegration during the period of functioning as a cathode.

4. An arc discharge lamp having discharge electrodes of a highly refractory material, said electrodes constructed and arranged in heat interchange relation to each other and to the anode of which an excess of energy is supplied to, thereby maintain their temperatures above that of disintegration during operation. Y

5. An arc discharge lamp having dis charge electrodes constructed and arranged so that one largely envelops the other and to the anode of whichan excess of energy is supplied, whereby heat isimpaited from the anode toJ the cathode during operation, to thereby maintain the temperature of the cathode above the temperature'of disintegration.

6. An electric discharge-tube with inclosed arc discharge having electrodes of refractory material in-an atmosphere of neutral gas, said electrodes being constructed and arranged so that upon supplying excess energy to the anode the electrode functioning as an anode imparts heatto the electrode functioning as a cathode, thereby maintaining the cathode temperature above that of disintegration.

In testimony whereof we aflix our signatures. l

GILLES HOLST. I I EKKO OOSTERHUIS. v JOI-IANNES BRUIJNES.

Ill 

